Process of treating materials electrolytically.



W. E. GREENAWALTL PROCESS OF TREATING MATERIALS ELECTROLYTiCALLY.

APPLICATION FILED MAY13,1913.

Patented Dec. 26, 1916.

mm W m W m W 2 m Ti E Q m 2 w 0 11 l MM WILLIAM E. GREENAWALT, OF DENVER, COLORADO.

FROCESS OF TREATING MATERIALS ELECTROLYTICALLY.

meas es.

Application filed May 13, 1913.

To all whom it may concern:

Be it known that I, WILLIAM E. GREENA- WALT, a citizen of the United States, residing in the city and county of Denver and State of Colorado, have invented certain new and useful Improvements in Processes of Treating Materials Electrolytically, of which the following is a specification.

It makes it possible to treat successfully such substances as copper matte, copper sulfid precipitate, cement copper, zmc oxid, copper oxid, lead sulfate, lead sulfid, metallic lead, etc. It also finds application in the electrolysis of solutions with insoluble anodes, where the disintegrated anode material has hitherto been a source of annoyance and expense.

In the treatment of substances such as .copper matte or copper sulfid precipitate,

the liberated sulfid ordinarily adheres tothe anode and thus increases-the electrical resistance to such an extent as to make the process unworkable. In the electrolysis of copper matte, as for example in the Marchese process, the deposited. copper was exceedingly impure and contained all impurities originally in the matte.- By my process these difficulties are easily overcome.

' In the refining of cement copper the custom is to smelt it to blister copper and then refine. it electrolytically. Such a method can only be carried out on alarge scale and is too expensive to be profitably worked in copper mining districts, and hence producers of cement-copper are obliged to market their product to the refineries or smelting companies, to their disadvantage. By my process the cement copper is at once refined, without fusion, and the precious metals obtained separately. Similarly, in the electrolysis of lead used as anode in sulfate solutions; the lead is peroxidized and forms a coating which increases the electrical resistance to a prohibitive degree, and its accumulation in the electrolyzer ultimately leads to short circuiting of the current and other disturbances, so that it has to be removed at frequent intervals at considerable expense, and hence lead anodes offer disadvantages so great as to be of little use. In this process these difficulties are overcome ;-'the peroxid of lead forms to a less degree and that which is formed is at once removed from the anode and from the electrolyzer, and consequently Specification of Letters Patent.

Patented Dec. 26, 1916., Serial No. 767,392.

from the sphere of disturbance of the electrio current.

This process also presents ideal conditions for the electrolysis of salts, such as copper oxid, zinc oxid, lead sulfate or sulfid, and so that the operation can be continuously and cheaply carried on.

Referring to the accompanying drawings, Figure 1 represents a suitable apparatus for carrying out the process, and Fig. 2 a modification.

In the figures 1 represents an electrolyzer having one electrode 2, at the bottom and the opposite electrode 3, suspended over it. Separating the two electrodes is a diaphragm 4, attached preferably to an electrode bell or frame 5, thereby forming a separate compartment. The diapflragrn and bell or frame are supported by suspenders 6,

which arearranged so that the frame, or bell, may be adjusted vertically, while being oscillated horizontally from pivotal points 21 bythe mechanism 7.

8 represents a flexible duct to permit the circulation of the electrolyte through the electrode bell while it is being oscillated, and flows into tank 10, from whence, by means of pump 11 and pipe 12, it may be returned to the electrode bell. Similarly, the solution may be circulated through the electrolyte tank by means of the pipe 13, to the tank 14', and returned to the electrolyte tank by means of the pump 15 and the pipe 16.

Having now given a description of the preferred apparatus, the process will be described, first, in the treatment of copper sulfid using the apparatus as shown in Fig. 1,

and second, using the apparatus as shown,

in Fig. 2.

Referring now more particularly to Fig. 1, the copper sulfid 20, which may be fused or unfused. granulated or in'slabs, is placed on the insoluble lead anode sheet in the bottom of the tank, in-an electrolyte of copper sulfate and sulfuric acid. The current is turned on and the cathode hell 5 oscillated by the mechanism 7. Ihe first effect of the oscillation is to make a muddy solution in the tank due to the agitation of the anolyte which brings the finer particles of copper suliid and liberated sulfur in suspension. were not the diaphragm the matter in suspension wr' ld get to the cathode and con taminate the d posit. The effect of the electrolysisis to decompose the copper sulfid, the copper being deposited on the cathode 3, and the sulfur liberated on the surface of the copper sulfid. The sulfur, being lighter than the copper sulfid, is readily brought into suspension in the anolyte due to the oscillation of the diaphragm and supporting frame, and by circulating the anolyte through pipe 13 to tank 14, where the sulfur is settled out, the clear solution may be pumped back to the electrolyte tank by means of pump 15 and pipe 16. Similarly the electrolyte may be circulated through the cathode compartment, especially if the deposit is spongy and does not adhere to the cathode. If thedeposit is spongy or granular it is detached from the cathode by the oscillating diaphragm and held in suspension until expelled from the electrolyzer,

and flows into tank 10 where the copper settles out and the clear solution pumped back to the cathode bell through pump 11 and pipe 12. If the deposit on .the cathode is firm, as'it will be if a low current density is used, the deposit isstripped from time to time, and the cathodes returned to the electrolyzer. In this way, it will be seen, that the work can progress continuously, the copper being deposited and the sulfur liberated and removed from the cell so that no deleterious results follow ts liberation. The gold, silver, and lead, and perhaps other metals, will be found in the anode sludge and may be removed as such, or with the sulfur, in suspension. If removed with the sulfur, they may be recovered whenthe sulfur is refined. The cross pieces on the anode bell supportingthe diaphragm, are efiective suspend them in the anode bell 5, and then in agitating the electrolyte in both the anode and cathode compartments, and thus are largely instrumental in promoting the process. These cross pieces may be transverse or lofigitudinal; the transverse arrangement is preferred. Deleterious gases from-'the under side of the diaphragm escapethrough the holes or saw cuts 22.

Suppose, now, that copper sulfid is to be electrolyzed in the modified apparatus, as shown in Fig. 2. As a preliminary step it is best to cast the sulfid into anodes, 3, and

make suitable electrical connections. A sheet copper cathode 2, is placed in the hottom of the electrolyte tank 1, to .receive the copper deposit. Whenthe current is turned on and the diaphragm oscillated, copper will be deposited on the cathode and sulfur released'at the anode, which owing to the oscillating diaphragm and consequent agitation of the electrolyte on the face of the anode, drops off, but is held in suspension in the electrolyte, and is withdrawn with. the electrolyte through pipe9, into the settling tank, where the sulfur is separated from the electrolyte and the electrolyte returned to the electrolyzer. In this way the circula tion is continued indefinitely, copper being deposited, and the sulfur continuously and automatically removed by means of the oscillating diaphragm.

If a depolarizing agent, such as sulfur dioxid, is to be. introduced into the electrolyte, it is best brought into solution in the settling tanks 10 and 14. Similarly, any substance capable of promoting the process, may be introduced in the electrolyte as it is circulated to effect the separationof the material in suspension, derived. from the electrolysis.

If cement copper is to be refined, it is placed on the lead anode 2, in the bottom of the tank and shown in Fig. 1 by '20, and the operation conducted as for copper sulfid. The precious metals and other valuable constituents may be subsequently recovered from the residual slimes.

If lead is used as the anode, in the electrolysis of'solutions, such as copper sulfate,

the peroXid formed from the lead anode 3, Fig. l, is removed from the anode and from the electrolyzer by the circulating electrolyte, due tothe'oscillation of the diaphragm.

By the .introduction of the oscillating diaphragm, as proposed in my process, the following distinctive results are attained: First; simultaneous agitation of both the anolyte and catholyte. Second; freeing of the insoluble disintegrated electrode material from the electrode and maintaining it in suspension in the electrolyte. Third; remov ing of the disintegrated electrode material from the electrolyzer and from the sphere of action of the electric current. preventing of the suspended matter "from getting to the deposited metal. Fifth; if

Fourth;

the diaphragm oscillates between stationary electrodes the expense of oscillation or mov-.

ing the heavy electrode material is entirely obviated. Sixth; removal of air andother gases from the diaphragm and from the electrodes, and thus preventing polarization, and the loss of efiiciency due to impoverishment of the electrolyte in contact with the electrodes. Seventh; the electrode plate in the bottom of the tank, which receives the material to be treated, is an eifective way of making electrical contact between a loose material and the conductor.

The process also finds application inthe direct refining of gold and silver precipitate as obtained either by the chlorination, cya

nid, or hyposulfit'e processes. It may also be employed to continuously remove spongy deposits from the cathode, and this action may go on simultaneously with the removal of the disintegrated or insoluble anode material. The loosening of the disintegrated material, such as lead peroXid, is facilitated by the introduction of a reagent, such as sulfur dioxid, and may be further facilitated by using an alternating current in connection with the direct current. If a depolarizer is used, the acid in the electrolyte is increased, and in this way its amount may be regulated.

The process also finds application in the electroylsis of lixiviants. such as cyanid in the treatment of gold and silver ores, whereby the metals may be deposited into a mercury cathode in the. bottom of the electrolyzer, and recovered as amalgam, from which the metals may be subsequently obtained by the distillation of the mercury.

If a material is electrolyzed in which the diaphragm may be dispensed with, the diaphragm may be omitted and the frame attached to the anode bell used as an agitator.

If the material to be electrolyzed is in afinely divided condition, either compartment may be regarded as the anode compartment, and either compartment may be regarded as the cathode compartment.

I claim:

1. An electrolytic process which consists in maintaining separate the anolyte and catholyte with a suitable diaphragm, simultaneously agitating both the anolyte and catholyte and withdrawing the electrolyte from one compartment and passing it through the other compartment without mingling with the electrolyte of the other compartment.

2. A process which consists in electrolyzing metallic salts in a finely divided condition which consists in simultaneously agitating both the anolyte and catholyte while maintaining separate the anolyte from the catholyte, and while maintaining a relative motion between the electrodes and the metallic salts being electrolyzed.

3. A processwhich consists in electrolyzing finely divided material in which the anolyte is separated by a diaphragm from the catholyte, and agitating the material to keep it in suspension during electrolysis, and maintaining a relative motion between the electrodes and the finely divided material being electrolyzed.

. 4:. A process which consists in electrolyzing finely divided material and agitating the material to keep it in suspension in the electrolyte during electrolysis while maintaining the anolyte separate from the catholyte, and withdrawing the electrolyte from one compartment and passing it through the other compartment without mingling with the electrolyte in the other compartment.

An electrolytic process which consists in maintaining separate the anolyte from the catholyte with a suitable diaphragm, simultaneously agitating both the anolyte and catholyte, subjecting the material being treated to the action of electrolysiswith a direct current with insoluble anodes thus causing adisintegration of the anode material, and facilitating the loosening of the disintegrated anode material by the action of an alternating current working in connection with the direct current.

VILLIAM E. GREENAWALT.

l/Vitnesses FRED L.'Soor'r, JESSIE G. SELLERS. 

